OBJECTIVE: To evaluate the association between pregnancy terminations and risk of breast cancer. DESIGN AND SETTING: Population-based case-control study in Wisconsin, Massachusetts, Maine, and New Hampshire. STUDY PARTICIPANTS: Cases were women younger than 75 years with a new diagnosis of breast cancer (n = 6888), identified from statewide tumor registries. Controls younger than 65 years (n = 9529) were randomly selected from lists of licensed drivers, or for older subjects, from lists of Medicare beneficiaries. EXPOSURES AND OUTCOMES: Breast cancer risk in relation to spontaneous or induced abortions. RESULTS: After adjustment for parity, age at first birth, and other risk factors, pregnancy termination (induced or spontaneous) was associated with a relative risk (RR) of breast cancer of 1.12 (95% confidence interval [CI], 1.04 to 1.21), compared with the risk among women who had never had a termination. Induced terminations were associated with a RR of 1.23 (95% CI, 1.00 to 1.51), which was somewhat greater than the risk associated with spontaneous terminations (RR, 1.11; 95% CI, 1.02 to 1.20). The association with induced abortions was stronger for those performed before legalization of abortion in 1973 (RR, 1.35; 95% CI, 1.01 to 1.80) than after this time (RR, 1.12; 95% CI, 0.84 to 1.49), suggesting a bias in reporting this sensitive procedure. CONCLUSIONS: A weak positive association was observed between abortion--whether induced or spontaneous--and risk of breast cancer. The increase in risk of breast cancer was somewhat greater among women with a history of induced terminations. However, this association may be due to reporting bias and was not significantly different than the slight risk for spontaneous terminations.
OBJECTIVE: To evaluate the association between pregnancy terminations and risk of breast cancer. DESIGN AND SETTING: Population-based case-control study in Wisconsin, Massachusetts, Maine, and New Hampshire. STUDY PARTICIPANTS: Cases were women younger than 75 years with a new diagnosis of breast cancer (n = 6888), identified from statewide tumor registries. Controls younger than 65 years (n = 9529) were randomly selected from lists of licensed drivers, or for older subjects, from lists of Medicare beneficiaries. EXPOSURES AND OUTCOMES: Breast cancer risk in relation to spontaneous or induced abortions. RESULTS: After adjustment for parity, age at first birth, and other risk factors, pregnancy termination (induced or spontaneous) was associated with a relative risk (RR) of breast cancer of 1.12 (95% confidence interval [CI], 1.04 to 1.21), compared with the risk among women who had never had a termination. Induced terminations were associated with a RR of 1.23 (95% CI, 1.00 to 1.51), which was somewhat greater than the risk associated with spontaneous terminations (RR, 1.11; 95% CI, 1.02 to 1.20). The association with induced abortions was stronger for those performed before legalization of abortion in 1973 (RR, 1.35; 95% CI, 1.01 to 1.80) than after this time (RR, 1.12; 95% CI, 0.84 to 1.49), suggesting a bias in reporting this sensitive procedure. CONCLUSIONS: A weak positive association was observed between abortion--whether induced or spontaneous--and risk of breast cancer. The increase in risk of breast cancer was somewhat greater among women with a history of induced terminations. However, this association may be due to reporting bias and was not significantly different than the slight risk for spontaneous terminations.
Authors: David H Brewster; Diane L Stockton; Richard Dobbie; Diana Bull; Valerie Beral Journal: J Epidemiol Community Health Date: 2005-04 Impact factor: 3.710
Authors: Eitan Friedman; Joanne Kotsopoulos; Jan Lubinski; Henry T Lynch; Parviz Ghadirian; Susan L Neuhausen; Claudine Isaacs; Barbara Weber; William D Foulkes; Pal Moller; Barry Rosen; Charmaine Kim-Sing; Ruth Gershoni-Baruch; Peter Ainsworth; Mary Daly; Nadine Tung; Andrea Eisen; Olufunmilayo I Olopade; Beth Karlan; Howard M Saal; Judy E Garber; Gad Rennert; Dawna Gilchrist; Charis Eng; Kenneth Offit; Michael Osborne; Ping Sun; Steven A Narod Journal: Breast Cancer Res Date: 2006-03-21 Impact factor: 6.466
Authors: F Fioretti; A Tavani; C Bosetti; C La Vecchia; E Negri; F Barbone; R Talamini; S Franceschi Journal: Br J Cancer Date: 1999-04 Impact factor: 7.640